GB1596964A

GB1596964A - Supplying weft in shuttleless looms

Info

Publication number: GB1596964A
Application number: GB1621978A
Authority: GB
Original assignee: Individual
Current assignee: Individual
Priority date: 1978-03-21
Filing date: 1978-04-25
Publication date: 1981-09-03
Also published as: DE2812266A1; CS213340B2; DE2812266C2

Description

(54) SUPPLYING WEFT IN SHUTTLELESS LOOMS (71) I, WALTER SCHEFFEL, a German Citizen of 8832 Weibenburg, Hopfenstr. 14, West Germany, do hereby declare the invention, for which I pray that a patent may be granted to me, and the method by which it is to be performed, to be particularly described in and by the following statement:- This invention relates to a weaving loom having a device for guiding and feeding the weft thread into the warp shed, the feeding or weft thread picking means comprising fluid jets through which the thread is guided and accelerated before it enters the shed.

In a weaving loom wherein the weft thread picking means comprise fluid jets for guidance and acceleration of the thread before it enters the shed, the control of these jets is a vital factor concerning minimal damage of the thread by the flow of the fluid. The problems associated with minimal damage of the thread tend to be mainly in evidence when the weaving loom is started up after standing still.

This explains why weaving looms which are not equipped with special control means for those jets, can work only with very tightly twisted threads or endless, continuously extruded yarns.

The risk of damge to or even destruction of the thread increases with the relative speed of the fluid medium and the thread. The most critical point is when the thread stops altogether. Controls are known, which interrupt the flow of fluid medium whenever the loom stops. Accordingly the control in question, usually a valve, has the function of preventing weft thread damage whenever the loom is not running.

However, this kind of device cannot prevent damage to, or destruction of the weft thread caused by the fluid medium during slow running periods of the loom, e.g. when the loom is accelerated or decelerated. Finally. this kind of arrangement has yet another drawback which causes frequent malfunctions. If the flow in the thread picking jets which guide the thread outside the shed is totally interrupted when the loom stops, the taut thread may slaken and get tangled.

Accordingly an object of the present invention is to provide a weaving loom in which the drawbacks referred to are overcome or at least minimised.

According to the invention, there is provided a weaving loom with weft feed from a stationary weft thread supply bobbin, comprising weft thread guiding and accelerating jets, which are situated outside of the shed at the picking side of the loom, a main drive shaft, the flow velocity in the jets being controlled in relation to the angular position and the angular velocity or r.p.m. of the main drive shaft.

The invention will now be described, by way of example, with reference to the accompanying drawings, in which: Figure 1 shows a circuit for controlling the flow velocity of weft thread guiding and accelerating jets of a weaving loom of the present invention; Figure 2 is a graph of fluid flow through said jets plotted against time, and thus shows the variation in fluid flow as the loom reaches a constant operating speed from rest; and Figures 3 to 5 show alternative forms of the circuit of Figure 1.

The weaving loom of the invention comprises a warp shed to which thread is fed from a stationary weft thread supply bobbin or cone, by means of a feeding mechanism including a feed roller, the thread entering the warp shed via weft thread guiding and accelerating jets 1 to 3 respectively, shown schematically in Figure 1.

All the jets are supplied with fluid by a supply pipe 11 which branches into a first line containing a manually adjustable or permanently set throttle valve 6 and a second line, in parallel with the first line, containing in series, an on-off valve 4 and a proportional valve 5. Upsteam of valve 5 and throttle 6, the first and second lines unite at a pipe 7 which is connected to a fluid supply, not shown.

The weaving loom has a main drive shaft which controls operation of both valves 4 and 5. On-off valve 4 is opened for picking the thread and closed afterwards. Thus it opens and closes periodically when the main shaft is in rotation, such opening and closing being arranged to take place at certain angular positions of the shaft. Proportional valve 5 opens at a certain minimal r.p.m. of the shaft and closes whenever the r.p.m. of the shaft drops below said value. The valve 5 is of a type which, once it is open, increases or decreases its throughput in accordance with the r.p.m. of the main shaft of the loom.

The function of the throttle 6 is to provide a small permanent flow through the jets 1 to 3, irrespective of the state of the valves 4 and 5. The small permanent flow ensures that the thread stays taut when the loom is stopped.

This prevents the thread becoming tangled up by its own elasticity and twisting.

Figure 2 is a graph showing fluid flow through the jets, as the vertical axis, with the horizontal axis being the time axis.

When the loom is at a standstill, time e, there is a certain amount of flow d. The magnitude of the flow, which is indicated by means of the dashed line F, is thus initially set by said throttle 6. When operation of the loom is started, the main drive shaft of the loom accelerates from zero r.p.m. to its final r.p.m.. The time required for such acceleration is indicated by time g.

During time g, the on-off valve 4 opens and closes several times for picking the thread.

These openings of the valve 4 are shown as time periods i with the acceleration time g.

Also during the acceleration time g, the r.p.m. of the drive shaft exceeds the minimal r.p.m. required for opening of the proportional valve 5. The valve S thus opens to allow flow of fluid, this flow increasing as the r.p.m. of the drive shaft increases upto its maximum. This increase in flow is shown by the rise in the line F in the time periods i when the valves 4 and 5 are both open.

Once the loom, and thus its main drive shaft, have reached constant operation, the fluid flow reaches its maximum value during each time period i when the valve 4 opens for picking the thread. Deceleration of the loom from said constant operation to a standstill occurs in the reverse manner.

Thus it will be appreciated that the flow velocity in the jets is controlled by both the angular position T and the angular velocity of the main drive shaft. The on-off valve 4 opens and closes in accordance with the angular position rp of the shaft and the proportional valve S opens and closes in accordance with the angular velocity zp of the shaft.

Figure 3 shows an alternative form of circuit compared to Figure I, in which a single combination valve 8 replaces the valves 4 and 5, and the throttle 6, the valve 8 being in a single pipe 7 connected to the fluid supply. The valve 8 is adjustable in the same way as the throttle 6 to provide a small permanent flow through the jets, irrespective of any other fluid flow thereto. Moreover the valve 8 also performs the same functions as the valves 4 and 5, i.e. it operates in accordance with the angular position and angular velocity of the main drive shaft of the loom. Instead of valve 8 including the throttle, the throttle could be separate and disposed in parallel to the valve 8.

Figure 4 shows a circuit similar to Figure 1, the difference being that the valve 5 is replaced by a switch or pilot valve 9 which opens to allow maximum throughput of fluid as soon as the r.p.m. of the drive shaft reaches a certain minimal value. Thus unlike the valve 5 of Figure 1, the flow does increase or decrease in accordance with the r.p.m. of the shaft once the valve 9 has opened. Such a valve 9 is of particularly simple construction and functionally reliable.

Figure 5 shows a circuit in which a combination pilot or switch valve 10 replaces the valves 4 and 9, and the throttle 6 of Figure 4, in the same way as the valve 8 of Figure 3 replaces the valves 4 and 5, and throttle 6 of Figure 1. Thus the valve 10 is disposed in a single pipe 7 connected to the fluid supply, in the same manner as the valve 8. As with the Figure 3 arrangement, the throttle could be separate from the combined valve and disposed in parallel thereto.

Activation of the valves 4 to 6, and 8 to 10 can be by conventional mechanical, electrical, pneumatic or hydraulic means, with activation of valves 5 and 9 being controlled in relation to the angular velocity of the drive shaft, activation of valve 4 being controlled in relation to the angular position of the drive shaft, and activation of valves 8 and 10 being controlled in relation to both of said drive shaft parameters.

WHAT I CLAIM IS: 1. A weaving loom with weft feed from a stationary weft thread supply bobbin, comprising weft thread guiding and accelerating jets, which are situated outside the shed at the picking side of the loom, a main drive shaft, the flow velocity in the jets being controlled in relation to the angular position and the angular velocity or r.p.m. of the main drive shaft.

2. A weaving loom as claimed in claim 1, wherein an on-off valve, which is periodically activated by a function of the angular position of the drive shaft, and a second valve, which is activated by a function of the angular velocity of the drive shaft, are provided in series for controlling flow velocity of the feed lines to the jets.

3. A weaving loom as claimed in claim 2, wherein the second valve is a proportional valve or a switch valve.

4. A weaving loom as claimed in claim 2 or claim 3, wherein a manually adjustable or

**WARNING** end of DESC field may overlap start of CLMS **.

Claims

**WARNING** start of CLMS field may overlap end of DESC **. shaft is in rotation, such opening and closing being arranged to take place at certain angular positions of the shaft. Proportional valve 5 opens at a certain minimal r.p.m. of the shaft and closes whenever the r.p.m. of the shaft drops below said value. The valve 5 is of a type which, once it is open, increases or decreases its throughput in accordance with the r.p.m. of the main shaft of the loom. The function of the throttle 6 is to provide a small permanent flow through the jets 1 to 3, irrespective of the state of the valves 4 and 5. The small permanent flow ensures that the thread stays taut when the loom is stopped. This prevents the thread becoming tangled up by its own elasticity and twisting. Figure 2 is a graph showing fluid flow through the jets, as the vertical axis, with the horizontal axis being the time axis. When the loom is at a standstill, time e, there is a certain amount of flow d. The magnitude of the flow, which is indicated by means of the dashed line F, is thus initially set by said throttle 6. When operation of the loom is started, the main drive shaft of the loom accelerates from zero r.p.m. to its final r.p.m.. The time required for such acceleration is indicated by time g. During time g, the on-off valve 4 opens and closes several times for picking the thread. These openings of the valve 4 are shown as time periods i with the acceleration time g. Also during the acceleration time g, the r.p.m. of the drive shaft exceeds the minimal r.p.m. required for opening of the proportional valve 5. The valve S thus opens to allow flow of fluid, this flow increasing as the r.p.m. of the drive shaft increases upto its maximum. This increase in flow is shown by the rise in the line F in the time periods i when the valves 4 and 5 are both open. Once the loom, and thus its main drive shaft, have reached constant operation, the fluid flow reaches its maximum value during each time period i when the valve 4 opens for picking the thread. Deceleration of the loom from said constant operation to a standstill occurs in the reverse manner. Thus it will be appreciated that the flow velocity in the jets is controlled by both the angular position T and the angular velocity of the main drive shaft. The on-off valve 4 opens and closes in accordance with the angular position rp of the shaft and the proportional valve S opens and closes in accordance with the angular velocity zp of the shaft. Figure 3 shows an alternative form of circuit compared to Figure I, in which a single combination valve 8 replaces the valves 4 and 5, and the throttle 6, the valve 8 being in a single pipe 7 connected to the fluid supply. The valve 8 is adjustable in the same way as the throttle 6 to provide a small permanent flow through the jets, irrespective of any other fluid flow thereto. Moreover the valve 8 also performs the same functions as the valves 4 and 5, i.e. it operates in accordance with the angular position and angular velocity of the main drive shaft of the loom. Instead of valve 8 including the throttle, the throttle could be separate and disposed in parallel to the valve 8. Figure 4 shows a circuit similar to Figure 1, the difference being that the valve 5 is replaced by a switch or pilot valve 9 which opens to allow maximum throughput of fluid as soon as the r.p.m. of the drive shaft reaches a certain minimal value. Thus unlike the valve 5 of Figure 1, the flow does increase or decrease in accordance with the r.p.m. of the shaft once the valve 9 has opened. Such a valve 9 is of particularly simple construction and functionally reliable. Figure 5 shows a circuit in which a combination pilot or switch valve 10 replaces the valves 4 and 9, and the throttle 6 of Figure 4, in the same way as the valve 8 of Figure 3 replaces the valves 4 and 5, and throttle 6 of Figure 1. Thus the valve 10 is disposed in a single pipe 7 connected to the fluid supply, in the same manner as the valve 8. As with the Figure 3 arrangement, the throttle could be separate from the combined valve and disposed in parallel thereto. Activation of the valves 4 to 6, and 8 to 10 can be by conventional mechanical, electrical, pneumatic or hydraulic means, with activation of valves 5 and 9 being controlled in relation to the angular velocity of the drive shaft, activation of valve 4 being controlled in relation to the angular position of the drive shaft, and activation of valves 8 and 10 being controlled in relation to both of said drive shaft parameters. WHAT I CLAIM IS:

1. A weaving loom with weft feed from a stationary weft thread supply bobbin, comprising weft thread guiding and accelerating jets, which are situated outside the shed at the picking side of the loom, a main drive shaft, the flow velocity in the jets being controlled in relation to the angular position and the angular velocity or r.p.m. of the main drive shaft.

permanently set throttle is provided in parallel with said periodically activated valve and said second valve, to maintain a minimum flow velocity in the jets irrespective of any flow through said valves.

5. A weaving loom as claimed in any one of claims 2 to 4, wherein the functions of said periodically activated valve and of said second valve are controlled by a single, doubly actuable combination valve.

6. A weaving loom as claimed in claim 5 when appended to claim 4, wherein said combination valve includes the function of the throttle.

7. A weaving loom as claimed in claim 1, wherein a valve, which is periodically activated by a function of the angular position of the drive shaft, and a switch valve, which comes into operation for switchover at a preselected angular velocity of the drive shaft and which is thus responsive to a function of said angular velocity, are provided in series for controlling flow velocity in the feed lines to the jets.

8. A weaving loom as claimed in claim 7, wherein a manually adjustable or permanently set throttle is provided in parallel with said periodically activated valve and said switch valve, to maintain a minimum flow velocity on the jets irrespective of any flow through said valves.

9. A weaving loom as claimed in claim 7 or claim 8 wherein the functions of said periodically activated valve and of the switch valve are combined in a single, doubly activated combination switch valve.

10. A weaving loom as claimed in claim 9, when appended to claim 8, wherein said combination switch valve includes the function of the throttle.

I I. A weaving loom substantially as hereinbefore described with reference to, and as shown in, Figures 1 and 2, or Figure 3, or Figure 4 or Figure 5 of the accompanying drawings.